1. Field of the Invention
The invention relates to a liquid discharge head, and more particularly to an ink jet recording head for recording by discharging a recording liquid into a recording medium, and a method for manufacturing the same.
2. Related Background Art
Conventionally, a flexible wiring substrate used as electric circuit substrate is composed of, for example, base film of polyimide resin or the like, a wiring layer of copper foil or the like, cover coat material of polyimide resin or thin film resist material, and adhesive for bonding them. This flexible wiring substrate is a thin and flexible substrate, and is blanked and formed by using die, laser, drill or other means, and is used in various parts in personal computer, ink jet recording apparatus or the like.
The flexible wiring substrate is often fixed and bonded to a product such as a support member or the like. For example, it is preferably used as an electric wiring member for a liquid discharge head. When used in the ink jet recording head as a typical application example of a liquid discharge head, the flexible wiring substrate may be peeled or swollen, depending on the type of the ink, due to mist caused by ink discharge or the like, and elution by ink may be possibly induced. Accordingly, it has been proposed to protect the end face of a blanking part (blanking end face) of the flexible wiring substrate by using a sealing agent.
Japanese Patent Application Laid-Open Nos. H10-044418 and 2002-19120 disclose an ink jet recording head protecting the blanking part end face of the flexible wiring substrate as shown in FIG. 1. More specifically, thermosetting adhesive or sealing agent made of epoxy resin or the like is used for covering electrical connection parts of the flexible wiring substrate and the discharge element substrate, and blanking end face of the flexible wiring substrate.
FIG. 2 is a diagram of flexible wiring substrate near electrical connection parts bonded to the support member of the ink jet recording head by thermosetting adhesive of epoxy resin or the like. FIG. 2 corresponds to magnified view near electrical connection parts in section 2-2 of the ink jet recording head in FIG. 1. Referring to FIG. 2, a discharge element substrate 101 has an orifice plate 106 including a discharge port 105 for discharging ink, and an electrode 107, and this electrode 107 and an electrode 108 of flexible wiring substrate 102 are electrically connected with each other. The discharge element substrate 101 is fixed to a support member 103 by means of an adhesive A111.
In the prior art shown in FIG. 2, first, the flexible wiring substrate 102 is formed into a desired shape by blanking by using a die. Next, a thermosetting adhesive B112 of epoxy resin or the like is transferred by a transfer plate on a predetermined position on the support member 103 to which the discharge element substrate 101 is bonded. By compressing and heating the flexible wiring substrate 102, the flexible wiring substrate 102 and the support member 103 are bonded by thermal compression. Further, a thermosetting sealing agent 110 of epoxy resin or the like is injected from a syringe into the electrical connection parts of the discharge element substrate 101 and flexible wiring substrate 102. By curing in an electric furnace, the blanking end face and electrical connection parts of the flexible wiring substrate 102 are coated.